Characterization of ionic conduction and electrode polarization relaxation processes in ethylene glycol oligomers

The complex relative dielectric function, dielectric loss tangent, electric modulus, alternating current electrical conductivity and impedance spectra of ethylene glycol oligomers (EGOs) i.e., ethylene glycol, diethylene glycol and poly(ethylene glycol)s of average molecular weight 200, 300, 400 and 600 g mol^-1 have been investigated in the frequency range 20 Hz to 1 MHz at 25 °C. These EGOs show the low frequency dielectric/electrical dispersion due to electrode polarization and ionic conduction effects. The ‘master curves representation’ of the real and imaginary parts of the intensive dielectric/electrical functions were used to evaluate the relaxation times corresponding to these effects processes. The comparative dielectric study of EGOs confirms that the values of low frequency relaxation times and direct current electrical conductivity are influenced by the chain flexibility and its random coiling.     

Three dimensional analysis of thermally loaded thick plates

A mixed three dimensional formulation is presented for the analysis of thermally loaded thick plates. The method developed follows the guidelines furnished by the Vlasov-Iyengar technique applicable to the analysis of mechanically loaded thick plates, in which the three dimensional governing equations are derived from the elasticity equations by using a MacLaurin series approach. The expressions for the components of displacement, stress, and heat flux as well as the temperature are obtained in a series form in terms of the linear partial differential operators operating on a set of initial functions, which are the solutions to the governing equations. The procedure to be followed in arriving at the solution is illustrated by solving the problem of the thermal bending of a clamped-supported thick square plate; it is found that the present solution deviates significantly from those of the lower order theories for large values of the thickness ratio.     

Dielectric dispersion study of coexisting phases of aqueous polymeric solution: Poly(vinyl alcohol) + poly(vinyl pyrrolidone) two-phase systems

The complex dielectric constant ?^∗(ω)=?^′−j?^″, electric modulus M^∗(ω)=M^′+jM^″, impedance Z^∗(ω)=Z^′−jZ^″ and ac conductivity dispersion behaviour of 5, 10 and 15 wt% concentration aqueous solutions of poly(vinyl alcohol) (PVA) (14?000 and 77?000 g mol⁻¹) and poly(vinyl pyrrolidone) (PVP) (24?000, 40?000 and 360?000 g mol⁻¹) and their binary mixtures were investigated in the frequency range 20 Hz to 1 MHz at 25 °C. Analysis of dielectric constant values confirms that hydrophilic effect of PVA in aqueous solution increases the real part of dielectric constant ?′, whereas for aqueous PVP solutions the hydrophobic effect masks the hydrophilic effect, which reduces ?′ values below 10 kHz. Low-frequency dielectric constant of these aqueous polymeric systems is sensitive to ionic conduction and electrode polarization. The monotonous change in various electrical properties with change in volume percentage of mixture constituents indicates that individual aqueous polymer system retains their own electrical properties in the aqueous two-phase polymeric system.     

Evolutionary concepts in the functional biotics arena: a mini-review

Over the years, the attempts to elucidate the role of beneficial microorganisms in shaping human health are becoming fairly apparent. The functional impact conferred by such microbes is not only transmitted by viable cells or their metabolites but also through non-viable cells. Extensive research to unveil the protective action of such wonder bugs has resulted in categorizing the beneficial microflora and their bioactive metabolites into a variety of functional biotic concepts based on their intended applications in various forms. In the modern era, these are often termed as probiotics, prebiotics, synbiotics, postbiotics, next-generation probiotics, psychobiotics, oncobiotics, pharmabiotics, and metabiotics. Currently, the concept of traditional probiotics is being widened to include microbes beyond lactic acid bacteria. Indeed, this diversification has broadened the functional food portfolio from food to pharmaceuticals. In this context, the present review aims to summarize the existing biotic concepts and their differences thereof.     

Binary crow search algorithm for the uncapacitated facility location problem

Neural Computing and Applications - The crow search algorithm (CSA) is a recently proposed population-based optimization algorithm for continuous optimization. Since the original CSA searches for a...     

Biogeography-based optimization scheme for solving the coverage and connected node placement problem for wireless sensor networks

Wireless Networks - In wireless sensor networks, coverage and connectivity are the fundamental problems for monitoring the targets and guaranteed information dissemination to the far away base...     

Dropout-error-rate calculations for a maximum-density study

This paper describes an experimental method for determining the maximum areal density achievable for a given head-to-tape interface (HTI). Using this method, we can calculate amplitude and bit-shift error rates during dropouts for the areal density the HTI is originally designed for, and beyond. First, the read-back waveform is sampled to obtain the amplitude distribution of signal samples below 50% clip level at each areal density. Second, the channel-transfer-function variation is investigated during a dropout to study its effect on the bitshift error rate. Third, empirical relationships between the areal density and an rms-to-rms signal-to-noise ratio (SNR) are obtained. Based on the above information, a theoretical model is presented that predicts the error rate for each areal density after a write skip (defined here as the soft-error rate). The calculated soft-error rate agrees well with its experimental counterpart. The technique presented here is useful in determining the upper limit of the HTI used in the paper.     

Studies on structural and optical behavior of nanoporous potassium-substituted magnesium ferrite nanomaterials,and their application as a hydroelectric cell

Journal of Materials Science: Materials in Electronics - In recent years, alkali metal substituted spinel magnesium ferrites have been considered as potential materials for the fabrication of...     

Evaluation of performance and emission behaviour of DI diesel engine powered by biofuel

In this experiment, the performance, emission, and combustion characteristics of a diesel engine were tested using bio-fuel (Anise oil) at different loads. The main focus of this study was to compare the existing biodiesel blends with the proposed mixture (anise?+?cerium oxide) of biodiesel blends in terms of engine parameters, cost, efficiency, and pollution control. The blends used in this experiment are B10 (Biodiesel-10%), B20 (Biodiesel-20%), and B30 (Biodiesel-30%). The emission and performance parameters considered for the test are SFC (specific fuel consumption), CO (carbon monoxide), NO_X (nitrogen oxide), and HC (hydrocarbon). These parameters were tested for different load conditions such as 0%, 25%, 50%, 75%, and 100%. From the results, it shows that SFC is lower for B20 blend compared to that of pure diesel fuel, while B10, B30, B40, and B50 blends have slightly higher values. From the experiment, it is found that emissions of the HC and NO_x were reduced and CO emission is slightly higher than the pure diesel.